Electric Field Aging In Aluminium Alloy And Al 2 E12 At 11:45-4 The Influence And Mechanism Of Cu Alloy Microstructure

During aging treatment, the different special effects can be caused by the influence of the electrostatic field compared with conventional heat treatment, but the impact laws and mechanism of action related research is not sufficient. In order to further understand the role of electrostatic field in the metal heat treatment process, the impacts of static electric field imposed during the aging process of10%cold-rolled pre-deformed2E12aluminum alloy and Al-4Cu alloy were researched by optical microscopy (OM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), Vickers hardness measurement and resistivity measurement. Conclusions are as followings:(1) The equilibrium concentration of aluminum vacancies was increased by the processing of the electric field, The resistivity of sample applied9kV/cm electric field at190℃was increased from2.72×10-6μΩ·cm to2.83×10-6μΩ·cm, which was closed to the sample without applied electric field at350℃; The process of the nucleation and growth of S’ phase which was nucleated at dislocation lines in2E12aluminum alloy was promoted by the higher aluminum vacancy concentration induced by electric field, and it hindered the decreasing of the dislocation density during recovery;(2) The formation of S phase during DSC analysis was accelerated by electric field, the exothermic peak of S phase was reduced by15℃. The calculation result showed that the maximum rate of phase transformation was increased by75%and the time needed to finish the transformation was reduced by20%.(3) Differences form the area near cathode to the area near anode appeared after190°C/4h aged treatment with electric field:the hardness of Al-Cu alloy was increased and increased to maximum of20%; the number of θ" phase precipitations was increased and even transformed to θ’ phase the supersaturation of Cu atoms in Al matrix was lower, the Lattice Constance increased from4.043A to4.045A;(4) The distribution of free electrons in the metal in electric field was calculated referred to the mode of carriers in semiconductor material when the boundary electric condition was changed. The result showed that the free electron density, Potential and electric field were different between areas. It was found that the vacancy formation energy of Al vacancy was calculated increased from0.68eV to0.78eV with the impact of0.001V/A electric field by first principle.